Tori Spelling‘s troubled marriage just took a twist she never saw coming.

After standing by her love rat husband Dean McDermott through a tawdry cheating scandal and subsequent rehab stay, RadarOnline.com has learned that Spelling has been hit with the ultimate heartbreak: He’s threatening to divorce her!

“Dean has finally had enough and he is tired of Tori playing the victim,” a source told Radar.

“Yes, Dean cheated on her, but Tori definitely played a role in where their marriage was when that happened. For months, Tori has railed on Dean and he has taken it. However, Dean has had it. Now he is threatening her with divorce.”

Mother-of-four Spelling’s decision to do a reality show in the midst of their marriage crisis was the last straw for McDermott, according to the source.

The mind-blowing clip features a distraught Spelling, 40, and flabbergasted McDermott at a counseling session with their marriage therapist in which they explore why he cheated on her and if their marriage can be salvaged.

“We have four kids, so in the sex department there were ebbs and flows. Is that safe to say?” McDermott said, looking at his wife.

“I can never give him enough sex,” she said through tears in another teaser. “He’s never going to be happy with just me.”

Spelling’s journey on the six-episode series will document the rocky road she navigates with McDermott following a marriage crisis when he was accused of infidelity and then his subsequent treatment in a rehab center.

Despite McDermott’s new divorce threats, the source added Spelling thinks it will blow over once the show premieres.